The technique of releasing canvassing data as if it was a proper poll in order to put the squeeze on Labour voters was first used by the Lib Dems in the Richmond Park by-election in 2016.
Then it worked very well with the total of LAB votes in the constituency on the night coming out out as fewer than the number of LAB party members in the seat.
After claiming last week that they were just 2% behind the Tories the LDs are now saying they are level pegging in Tiverton and Honiton which votes in the by-election on Thursday.
What is clear is that the Tory are fighting very hard in order to avoid to avoid the double disaster of losing two Westminster by-elections on the same night. Wakefield, where the former Tory MP is in prison, votes at the same time and is seen as near certain LAB gain.
In the Tiverton and Honiton betting the LDs are now a 73% chance.